Specific heat study of the CDW phase transition in the doped blue bronzes Tl0.3-xKxMoO3

The specific heat of the doped blue bronzes Tl0.3-xKxMoO3 (x = 0.06, 0.15) has been measured in the temperature range between 100 and 220 K. Anomalies were observed at 165.7 K and 164.8 K for Tl0.24K0.06MoO3 and Tl0.15K0.15Mo O3, respectively. The specific heat jump, and the entropy and enthalpy chan ges associated with the CDW phase transition are estimated. The results sug gest that the Peierls phase transition is of second order. By analogy with the behavior of pure Tl0.3MoO3, it shows that in the quasi-one-dimensional blue bronze, the perfect order of the interlayer alkali or thallium polyhed ral chain plays an important role in the Peierls phase transition.